New Publications. 431 



parts of the nervous system. One or two small corpuscles are soon 

 doveloped in this liquid, whoso form, size, and oscillatory movements 

 are in every respect similar to those of the otolithes in the perfect 

 animal. The vesicle or bladder containing them has a double margin 

 round the outside, resulting probably from the walls becoming thicker. 

 The size of the otolithes is from ^\-^ to ^\^ of a line (0*005 to 

 0'0075 millimetre) ; their number goes on gradually increasing, and 

 reaches a score, when the lymnia quits the shell ; the diameter of 

 the vesicle or bladder, at this time, is about jV ^^ ^ ^^"g (0*066 

 millimetre). Besides the otolithes, other small corpuscles are found, 

 of smaller size, which often do not reach the dimensions of y^Vir 

 of a line (0*0023 millimetre). The number of otolithes, and the 

 size of the auditory vesicle or bladder, then continue to augment ; at 

 the same time the animal continues to grow. When in the adult 

 state, we can reckon from 100 to 200 otolithes, and the diameter 

 of the bladder varies from -^-^ to y'^ of a line (0*14 to 0*23 milli- 

 metre). 



The development of the auditory apparatus presents the same 

 phenomena in the Physes, Paludines, and terrestrial Gasteropods in 

 general (helix, limaces, &c.) There is no difference except in the 

 size of the parts. 



Among bivalves, the apparatus of the ear contains only a single 

 otolithe of a large size, which fills the cavity of the bladder. The 

 same disposition is found in the embryo of these molluscs before 

 issuing from the egg ; the otolithe, smaller than in the adult, exhi- 

 bits very lively oscillatory movements, as it does in the latter. 



NEW PUBLICATIONS RECEIVED. 



1. A History of British Fossil Mammals and Birds. By Richard 

 Owen, F.R.S., F.G.S., &c. 8vo, pp. 560, with 237 woodcuts. John 

 Van Voorst, Paternoster Row, London. 1846. This original, able, 

 accurate, and important, contribution to the Palaeontology of Britain, 

 already more fully noticed in this volume of the Edinburgh New Philo- 

 sophical Journal, from page 338 to page 343, is, long ere this, in the 

 hands of every British Palceontologist. 



2. Thoughts /)n Animalcules, or a Glimpse of the Invisible World, 

 revealed by the Microscope. By G. A. Mantell, LL.D., F.R.S. John 

 Murray, Albemarle Street, London. 1846. This beautiful and inter- 

 esting volume, like most of Mr MantelVs writings, has an agreeable 

 popular cast. It combines so much good scientific details and infer- 

 ences as will render it acceptable to an extensive class of readers. 



3. A History of the Fossil Insects in the Secondary Rocks of Eng- 

 land. By the Rev. P. B. Brodie, M.A., F.S.S. John Van Voorst, 

 Paternoster Row, London. 1846. The Palceontological History of 

 Itisects has hitherto been so little cultivated that naturalists will receive 

 with pleasure Mr Brodie's valuable volume, which we recommend to the 

 particular notice of Palaeontologists. 



